CODEWITHSUNDEEP
r
Grippa
Grippa

Reputation: 13

Combine vector with different lengths in R

FIRST SITUATION:

I have the vectors v1 and v2 v1 <- c(1, 2, 4, 5, 7, 8, 10, 11, 13, 15) v2 <- c(3, 4, 5, 23, NA, 14, NA)

I want to create a function (I don't want want use r functions for these 3 cases) to sum each values and because the length is different, I want to put a 0 in this missing places.

As a result, i would like to have: 4, 6, 9, 28, NA, 22, NA, 11, 13, 15

SECOND SITUATION

I want to sum each values, just like the first situation, but the sum action must stop when reaches the last value of the smaller vector.

As a result, it would be: 4, 6, 9, 28, NA, 22, NA

THIRD SITUATION

I want to combine each values and repeat them when the there is a smaller one.

As a result, it would be: 4, 6, 9, 28, NA, 22, NA, 14, 17, 20

Upvotes: 0

Views: 139

Answers (1)

akrun
akrun

Reputation: 886948

We can get the length same

mx <- max(length(v1), length(v2))
c(v2, rep(0, mx - length(v2))) + c(v1, rep(0, mx - length(v1)))
#[1]  4  6  9 28 NA 22 NA 11 13 15

For second situation, use min

mn <- min(length(v1), length(v2))
v2[seq_len(mn)] + v1[seq_len(mn)]
#[1]  4  6  9 28 NA 22 NA

Or for third situation

c(v2, v2[seq_len(mx - length(v2))]) + c(v1, v1[seq_len(mx - length(v1))])
#[1]  4  6  9 28 NA 22 NA 14 17 20

It can be converted to a function

 f1 <- function(vec1, vec2, method = "min") {
       switch(method, 

           min = {
                  mn <- min(length(vec1), length(vec2))
                  vec1[seq_len(mn)] + vec2[seq_len(mn)]
                  },
            max = {
                 mx <- max(length(vec1), length(vec2))
                 c(vec2, rep(0, mx - length(vec2))) + c(vec1, rep(0, mx - length(vec1)))},
             recycle = {
               mx <- max(length(vec1), length(vec2))
                c(vec2, vec2[seq_len(mx - length(vec2))]) + c(vec1, vec1[seq_len(mx - length(vec1))])
             })
         }


f1(v1, v2)
#[1]  4  6  9 28 NA 22 NA
f1(v1, v2, "max")
#[1]  4  6  9 28 NA 22 NA 11 13 15
f1(v1, v2, "recycle")
#[1]  4  6  9 28 NA 22 NA 14 17 20

Upvotes: 1

Related Questions